In many wireless communication systems, a node within the system will need to determine its location. Nodes determining, or estimating, their locations will be capable of utilizing any one of multiple location estimation techniques, depending on the various requirements of the node (e.g., desired location accuracy, computational intensity, tracking capabilities, . . . , etc.). Such location estimation techniques include solutions such as weighted-average location techniques, path loss techniques, a global-positioning system (GPS) technique, Time-Difference of Arrival (TDOA) techniques, . . . , etc.
One location-estimation technique that may be utilized by nodes is a maximum-likelihood (ML) based relative location algorithm such as that described in U.S. Pat. No. 6,473,038. This technique allows a node wishing to determine its location itself to utilize location estimates of other nodes in an iterative process. It is important for a node utilizing an ML-based location technique to know the location estimation techniques used by its neighbors. This is because the ML cost function is a global problem solved in a distributed manner by nodes in the communication system. Therefore, each individual node solves a piece of a bigger optimization problem. If one of a node's neighbors uses a nearest-neighbor technique to calculate its location, perhaps as required by an application, then the resulting location error that would be passed on through coordinate sharing could be very large. Such an error would propagate through the other nodes that use ML to estimate their location, potentially lowering the accuracy of any location estimate in the system.
Thus, in a network with multiple location solutions, it is imperative that nodes have a way to identify the location estimation technique used to obtain the coordinates being exchanged. Therefore, a need exists for a method and apparatus for transmitting location data within a communication system that allows a node participating in location estimation to utilize an appropriate subset of location coordinates received from other nodes.